Plating baths and plating additives heretofore utilized include those set forth in U.S. Pat. No. 3,755,096 to Passal; U.S. Pat. No. 3,875,029 to Rosenberg et al; U.S. Pat. No. 3,977,949 to Rosenberg; U.S. Pat. No. 4,061,547 to Rosenberg; and U.S. Pat. No. 4,072,582 to Rosenberg. However, none of these plating baths or tin brighteners are pertinent since they do not teach or suggest the additives of the present invention.